Copolymer, ink including copolymer, and ink-stored container

Abstract

A copolymer including a structural unit represented by General Formula (1) below, and a structural unit represented by General Formula (2) below, where, in General Formula (1), R 1 is a hydrogen atom or a methyl group, L 1 is an alkylene group having 2 or greater carbon atoms but 5 or less carbon atoms, and X is a hydrogen atom or a cation, where, in General Formula (2), R 2 is a hydrogen atom or a methyl group and L 2 is an alkylene group having 2 or greater carbon atoms but 18 or less carbon atoms.

What is claimed is: 
     
       1. A copolymer comprising:
 a structural unit represented by General Formula (1) below; and 
 a structural unit represented by General Formula (2) below, 
 
       
         
           
           
               
               
           
         
         where, in General Formula (1), R 1  is a hydrogen atom or a methyl group, L 1  is an alkylene group having 2 or greater carbon atoms but 5 or less carbon atoms, and X is a hydrogen atom or a cation, 
       
       
         
           
           
               
               
           
         
         where, in General Formula (2), R 2  is a hydrogen atom or a methyl group and L 2  is an alkylene group having 2 or greater carbon atoms but 18 or less carbon atoms. 
       
     
     
       2. The copolymer according to  claim 1 ,
 wherein a molar ratio of the structural unit represented by General Formula (1) to the structural unit represented by General Formula (2) (the structural unit represented by General Formula (1):the structural unit represented by General Formula (2)) is from 0.5:1 through 3:1. 
 
     
     
       3. The copolymer according to  claim 1 ,
 wherein, in the structural unit represented by General Formula (2), L 2  is an alkylene group having 2 or greater carbon atoms but 12 or less carbon atoms. 
 
     
     
       4. The copolymer according to  claim 1 ,
 wherein the copolymer is formed by polymerizing a compound represented by General Formula (3) and a compound represented by General Formula (4), 
 
       
         
           
           
               
               
           
         
         where, in General Formula (3), R 1  is a hydrogen atom or a methyl group, L 1  is an alkylene group having 2 or greater carbon atoms but 5 or less carbon atoms, and X is a hydrogen atom or a cation, 
       
       
         
           
           
               
               
           
         
         where, in General Formula (4), R 2  is a hydrogen atom or a methyl group and L 2  is an alkylene group having 2 or greater carbon atoms but 18 or less carbon atoms. 
       
     
     
       5. An ink comprising:
 water; 
 a coloring material; and 
 a copolymer, 
 wherein the copolymer is a copolymer including: 
 a structural unit represented by General Formula (1) below; and 
 a structural unit represented by General Formula (2) below, 
 
       
         
           
           
               
               
           
         
         where, in General Formula (1), R 1  is a hydrogen atom or a methyl group, L 1  is an alkylene group having 2 or greater carbon atoms but 5 or less carbon atoms, and X is a hydrogen atom or a cation, 
       
       
         
           
           
               
               
           
         
         where, in General Formula (2), R 2  is a hydrogen atom or a methyl group and L 2  is an alkylene group having 2 or greater carbon atoms but 18 or less carbon atoms. 
       
     
     
       6. The ink according to  claim 5 ,
 wherein the coloring material is a pigment. 
 
     
     
       7. The ink according to  claim 5 , further comprising:
 a water-soluble organic solvent, or a surfactant, or both. 
 
     
     
       8. An ink-stored container comprising:
 an ink; and 
 a container storing the ink, 
 wherein the ink includes: 
 water; 
 a coloring material; and 
 a copolymer, 
 wherein the copolymer is a copolymer including: 
 a structural unit represented by General Formula (1) below; and 
 a structural unit represented by General Formula (2) below, 
 
       
         
           
           
               
               
           
         
         where, in General Formula (1), R 1  is a hydrogen atom or a methyl group, L 1  is an alkylene group having 2 or greater carbon atoms but 5 or less carbon atoms, and X is a hydrogen atom or a cation, 
       
       
         
           
           
               
               
           
         
         where, in General Formula (2), R 2  is a hydrogen atom or a methyl group and L 2  is an alkylene group having 2 or greater carbon atoms but 18 or less carbon atoms.